Susan, 49, found out the news today (Wed) when the latest US charts were announced.
Her new album, called The Gift, sold more than 317,000 copies in the US in its first week of release.
The album also reached the top of the UK charts on Sunday.
Susan has become only the third act ever to secure the accolade in a 12-month period.
Only The Monkees in 1967 and The Beatles two years later managed to do the same.
Susan has also become the first ever UK act to secure No1 US albums with their first two releases.
A delighted Simon Cowell, 51, said: “I’m thrilled for Susan, she has once again defied the odds. She is my superwoman.”
Susan added: “I’ve never felt happier in all my life. This is an amazing result and one I never expected.”